docs: def get_source_and_pgp_key(source_and_key):
      """Look for a pgp key ID or ascii-armor key in the given input.
  
      :param source_and_key: Sting, "source_spec|keyid" where '|keyid' is
          optional.
      :returns (source_spec, key_id OR None) as a tuple.  Returns None for key_id
          if there was no '|' in the source_and_key string.
      """
      try:
          source, key = source_and_key.split('|', 2)
          return source, key or None
      except ValueError:
          return source_and_key, None